Oracle error
ORA-30036
ORA-30036: unable to extend segment by %s in undo tablespace '%s'
What usually causes it
Undo is full of active (uncommitted) undo, or of unexpired undo when retention is guaranteed.
What to check first
Find the large open transactions first, then add space to the undo tablespace if needed.
Scripts that help
- Open transactions and the undo they holdEvery open transaction with its session, undo size and start time. An old transaction from an idle session is usually someone who forgot to commit.
- Undo usage and ORA-01555 riskUndo extents by status, then the longest query and any snapshot-too-old or out-of-space errors from V$UNDOSTAT (roughly the last four days).
- Add space: resize or add a datafileTemplates for the three usual fixes. The resize runs as written; the other two are commented out. Change names and sizes, and uncomment the one you…